1. Field of the Invention
The present invention relates to a smart card system, and more particularly to a smart card system that can prevent scratching of contacts of a smart card by contact members of a card reader while the smart card is being inserted into or taken out of the card reader, thereby reducing damage to the contacts and preventing a malfunction of an electric signal between contacts and a detect switch.
2. Prior Arts
As is well known, a smart card system includes a smart card having an integral circuit therein, and a card reader for reading and/or writing information stored in the integral circuit of the smart card. Recently, such smart card system is widely used as a means for watching a pay-per-view program of a satellite-based broadcasting station, and as a means for managing information about subscribers.
Generally, the integral circuit includes a PROM(programmable read only memory), a RAM(random access memory) and a CPU(central processing unit). The smart card has a plurality of contacts connected to the integral circuit, and the card reader has contact members that contact the contacts of the smart card. When the smart card is inserted into the card reader, the card reader reads information stored in the PROM and the RAM, and sends an electric signal, such as a control signal, to a writing device.
FIGS. 5 to 8 show a conventional smart card system. As shown in FIG. 5 a conventional smart card system 500 includes a smart card 510 and a card reader 515. Smart card 510 is formed therein with an integral circuit section 512 having a PROM, a RAM and a CPU. A plurality of contacts 514, which are connected to integral circuit section 512, are arranged on an upper surface of smart card 510.
Card reader 515 comprises an upper frame 520 and a lower frame 550. When assembled together, upper and lower frames 520 and 550 form an insertion hole 522, into which smart card 510 is inserted. Upper frame 520 of card reader 515 is formed at an upper surface thereof with first and second apertures 524 and 526. First aperture 524 is separated from second aperture 526 by a guide bar 540. A plurality of first and second contact members 542 and 544 are provided in card reader 515 so as to make contact with contacts 514 of smart card 510. First ends of first and second contact members 542 and 544 are respectively embedded into first and second side bars 532 and 534 which are constituting parts of upper frame 520. In addition, second ends of first and second contact members 542 and 544 extend up to guide bar 540 by crossing first and second apertures 524 and 526, respectively.
The second ends of first and second contact members 542 and 544 are bent in an arc shape and are seated on an upper surface of lower frame 550 so that they can with contact with contacts 514 of smart card 510 when smart card 510 has been inserted into card reader 515. In general, the number of first and second contact members 542 and 544 is equal to the number of contacts 514.
In addition, at a predetermined position of an under surface of 534, there is provided a detect switch 530 for detecting the insertion of smart card 510. Guide bar 540 is formed with a plurality of guide slots for guiding the upward movement of first and second contact members 542 and 544.
FIGS. 6 to 8 are sectional views showing smart card 510 in the process of being inserted into card reader 515. While smart card 510 is being moved to a first position in card reader 515 as shown in FIG. 6, a lead end of smart card 510 makes sliding-contact with the second ends of first contact members 542, which are seated on the upper surface of lower frame 550. Thereby the second ends of first contact members 542 move upward along the guide slots of guide bar 540.
Then, while smart card 510 is being moved to a second position in card reader 515 as shown in FIG. 7, the lead end of smart card 510 makes sliding-contact with the second ends of second contact members 544, which are also seated on the upper surface of lower frame 550, thereby the second ends of second contact members 544 moving upward along the guide slots of guide bar 540.
When smart card 510 reaches a third position in card reader 515 as shown in FIG. 8, that is a reading position, the second ends of first and second contact members 542 and 544 with contact with contacts 514 provided on the upper surface of smart card 510. At this time, the lead end of smart card 510 pushes detect switch 530 disposed at a terminal end of card reader 515, so detect switch 530 begins to switch on.
As detect switch 530 is switching on, card reader 515 reads information stored in integral circuit section 512 of smart card 510 through first and second contact members 542 and 544 contacted with contacts 514, and sends an electric signal based on the information to a writing device.
However, in smart card system 500, contacts 514 of smart card 510 make slide-contact with first and second contact members 542 and 544 of card reader 515, so that first and second contact members 542 and 544 scratch contacts 514 of smart card 510 while smart card 510 is being moved to the reading position in card reader 515, thereby resulting in damage to contact 514.
Particularly, when smart card system 500 is used for the purpose of watching the pay-per-view programs of a satellite-based broadcasting station, this kind of damage to contacts 514 may vary characteristics of an electrical control signal, thereby resulting in a malfunction such as an inferior picture or noise.
On the other hand, U.S. Pat. No. 4,839,509 issued to Yasuma et al. discloses a connector device for preventing contacts of a smart card from being damaged. However, Yasuma's connector device requires a plurality of mechanical parts so as to move the smart card to the reading position. For this reason, Yasuma's connector has a complicated structure and a large size.